1. Field of the Invention
The invention in general relates to the heat-treating of a workpiece by an energy beam, and in particular to apparatus for controlling the impingement of the beam on the workpiece.
2. Background Information
An energy beam such as a laser is often used in metal processing operations to create a thin, hard outer surface on a metallic workpiece.
Some workpieces, for example gears, have recesses into which the laser beam is directed for accomplishing a heat-treating operation. It is possible to direct narrow, low power laser beams with great accuracy; however, the generally broader, high power beam such as from a carbon dioxide laser used for such operations are more difficult to precisely control. As will be brought out, such high power laser beam operations often produce less than satisfactory results, particularly on gear teeth wherein the gear turns in both directions.